Optus has followed Telstra in announcing its iPhone 4 plans, with a good selection of options on offer and no sign whatsoever of the "tethering charge" which it controversially promoted for the iPhone 3GS.
Like Telstra, Optus is concentrating most of its marketing effort on its cap plans. The information sent out to media and to pre-registered customers (reproduced below) emphasises those plans with 1GB of data or more, but Optus is also offering cheaper plans with lower data inclusions and higher-cap Timeless Extreme offers.
As Nick over at Gizmodo points out, the big contrast between Optus' plans and those from Telstra is the more generous data allowances. That said, Telstra's broader network coverage will be an attraction for many people, and we don't yet have prices from Vodafone or 3.